Numbers 29:1
"And in the seventh month, on the first day of the month, ye shall have an holy convocation; ye shall do no servile work: it is a day of blowing the trumpets unto you."
Cross References (ranked by relevance)
And it shall come to pass in that day, that the great trumpet shall be blown, and they shall come which were ready to perish in the land of Assyria, and the outcasts in the land of Egypt, and shall worship the LORD in the holy mount at Jerusalem.
Thus all Israel brought up the ark of the covenant of the LORD with shouting, and with sound of the cornet, and with trumpets, and with cymbals, making a noise with psalteries and harps.
And the LORD shall be seen over them, and his arrow shall go forth as the lightning: and the LORD God shall blow the trumpet, and shall go with whirlwinds of the south.
From the first day of the seventh month began they to offer burnt offerings unto the LORD. But the foundation of the temple of the LORD was not yet laid.
Blessed is the people that know the joyful sound: they shall walk, O LORD, in the light of thy countenance.
So the priests, and the Levites, and the porters, and the singers, and some of the people, and the Nethinims, and all Israel, dwelt in their cities; and when the seventh month came, the children of Israel were in their cities.
Blow up the trumpet in the new moon, in the time appointed, on our solemn feast day.